Discharge block



sept. 3, 1929; w, COOK 1,726,807

DI S CHARGE BLOCK Filed May l 1924 W//Qcl 600% Patented Sept. 3, 1929.

UNITED STATES WALLACE L. COOK, OF CHICAGO, ILLINOIS, ASSIGNOIR, T0 THERELIABLE ELECTRIC CO.,

0F CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

DISCHARGE BLOCK.

Application filed May 1,

My invention relates to lightning arresters and more particularly to adischarge block for lightning arresters.

It is a purpose of the invention to provide a new and improved dischargeblock for a lightning arrester which comprises a sawtooth edged memberor other member having sharp projections thereon that is placed in closeproximity to a ground plate or block of conductingmaterial connectedwith the ground, and to provide new and improved means for mounting thesame in an insulating supporting member. Said member having theplurality of projections or discharge points thereon is preferablymolded in the insulating material in any suitable manner as by providingopenings in the conducting member having the discharge points into whichthe insulating material enters when the device is molded to iirmly holdthe conducting member in position in the insulating material.

It is another purpose of the invention t0 provide an insulating mountingfor a conducting member which is provided with means for spacing theconducting member with its discharge points at a predetermined distancefrom the ground plate or block and with means for receiving a holdingmember such as a spring to hold the insulating member and the conductingmember in a predetermined relationship relative to the ground plate orblock and to prevent lateral shifting of the insulating member relativeto said ground plate.

It is still a further purpose of the invention to provide an insulatingmounting for the conductin member having the discharge points which iasthe property of becoming somewhat plastic upon heating thereof so thatthe pressure of the holding spring thereon will cause the same to besomewhat fiattened to thereby bring the conducting member having thedischarge points into positive grounding engagement with the conductingmember mounted on the ground plate so as to insure absolute discharge tothe ground through said conducting member and said ground plate. Theinsulating member is preferably provided with flanges that engage withthe conducting member connected with the ground so that said flangeswill be readily distorted and thus shortened due to pressure of theholding spring on the insulating member when heated to provide apositive rounding connection as referred to above. uch heat- 1924.Serial No. 710,281.

ing, of course, takes place when a discharge of lightning occurs throughthe device.

Any number of conducting discharge members may be provided, the onedevice being shown in the drawings as having a single discharge memberand in another form a plurality of discharge members is shown.

Other objects and advantages of the invention will appear as thedescription of the accompanying drawings proceeds. However, I desire tohave it distinctly understood that I do not intend to limit myself tothe exact details shown or described but that I intend to include aspart of my invention all such ob` vious changes and modifications ofparts as would occur to a person skilled in this art and as would fallwithin the scope of the claims.

In the drawings:

Fig. 1 is a transverse section partly broken away of a supporting membershowing my improved discharge block mounted thereon in co-operativerelationship with a ground plate and a conducting material block mountedthereon;

Fig. 2 is a section taken on the line 2-2 of Fig. 1, partly broken away;

Fig. 3 is a similar section showing the position of the parts afterheating;

Fig. 4 is a bottom plan view of the discharge block shown in Figs. 1 to3 inclusive; and

Fig. 5 is a similar view of a slightly modied form of the device.

Referring in detail to the drawings, a supporting member of any form ofinsulating material 10 is shown in Fig. 1 to Fig. 3 inclusive upon whichis mounted a ground plate 11 and co-operating with said ground plate arecarbon or other conducting material blocks, one only being shown in thedrawings and being indicated by the numeral 12. With cach of said blocks12 a discharge block cooperates which forms the subject matter ofthepresent invention.

The discharge block comprises a. main body portion 13 of insulatingmaterial, said member 13 being provided with flanges 14. The fianges, itwill be noted, dene a recess 16 in one face of the block. The oppositeface of the block 18 is provided with a longitudinally extending grooveor recess 17 which is adapted to receive the holding spring 18 which ismounted on the member 10 by means of the bolt or other securing member19 which also clamps said member 18 to a conducting strip 20 that leadsto any suitable apparatus that Cil 24 so as to key the conductingdischarge member 22 in the block of insulating material 13. Thedischarge member 22 is provided witha plurality of discharge pointswhich in the drawings are shown as beinginthe form of a sawtooth edgedporti-on 25, the extreme outer edges or peaks 26 of saidsaw teeth beingspaced a slight distance from the carbon block 12 in thenormal positionofthe device,

as will be clear from Fig. 2. Thus, the ordinary currentspassingthrough` the apparatus to which the spring `18 is connected willnot discharge across the gap between the point of the saw teeth 26 andthe carbon block 12. However, in the case of a lightning discharge orother high potential being applied to the apparatus, a discharge willoccur across the gap from the saw teeth to the carbon block and asaresult of said discharge a large amount of heat will be generated.Preferably, the member 13 is made of such non-conducting materialthatthe same will melt somewhat or become somewhat plastic when such heatingoccurs. This will cause the fiange portions 14 to be distorted or breakdown in the manner indicated in Fig. 3 by the numeral 27 and theHattening or shortening of the flanges 14lwill continue to such anextent that` the saw teeth 25 will finally engage firmly with the block12 thus acting as a stop to limit the movement of the block 13, due topressure of the spring 18 thereon, and when this occurs there will'be apositive oonnection between the sawtooth discharge member and the groundplate 11 through the block 12, or, in other words, there will be apositive ground between the conducting strip 20 and the ground plate 11.

ln Fig. '5 a slightly modified form of the device is shown, in which theinsulating block 13 is provided with flanges 14 defining a recess 16,said block having mounted therein a pluralitv of discharge plates orstrips 22 which are preferably sow-tooth edged and are mounted bymolding in the said block in a similar manner to the strips 22.

It will be noted that by providing the discharge member 20 molded in theinsulating block 13 a predetermined spacing between the saw-teeth pointsand the carbon or other conducting material bloc-k connected with theground is obtained as the said. members can be molded in the materialwith almost absolute accuracy as to the spacing thereof relative to theflanges 14 without any necessity of grinding any parts.

The material used for the discharge blocks may be of any suitableinsulating composition which will soften when heated sufficiently tocause the action to take place which is illustrated in Fig. 3. Acomposition embodying shellac is preferably used.

Having thus described my invention, what "l desire to claim and secureby United States Letters Patent is:

1. ln a device of the character described, a support, a groundedconducting member motmtedthereon, and a discharge block cooperatingtherewith, said discharge block comprising an insulating member ofmaterial becoming plastic when heated above a predetermined tempera-tureand a conducting discharge member moulded in said insulating member,said insulating member carrying and supporting said discharge member inspaced relation to said grounded member, said discharge member having aplurality of discharge points spaced a predetermined ldistance from saidgrounded conducting member when said insulating member is in engagementtherewith and having openings therein into which the material of saidinsulating member extends to hold Vsaid discharge member in fixedposition in said block.

2. ln a device of the character described, a support, a plane facedgrounded member of conducting material mounted thereon, a dischargeblock comprising a body portion of insulating material, aconductingdischarge member carried by said body portion and normally held inspaced relation to said grounded member, and means for clamping saiddischarge block in engagement with said grounded member, said insulatingbody portion having spaced supporting flange portions on opposite sidesof the discharge member engaging the plane face of said grounded memberyieldable und-er the influence of said clamping means at a temperatureabove normal atmospheric temperature.

3. ln a protective device of the character described a discharge blockcomprising a rectangular body portion of insulating material becomingplastic when heated above a predetermined temperature, and havinggrooves in two opposing sides thereof, a conducting discharge membermoulded in said body portion having opposite side edges exposed in saidgrooves, one of said edges extending into one of said grooves and spacedfrom the top thereof whereby said body portion serves as means to spacethe discharge edge from a grounded surface and as a protecting means forsaid edge.

4. ln a device of the character described a support, a grounded memberof conducting material mounted thereon, a discharge block comprising abody portion of insulating material, becoming plastic when heatedabove apredetermined temperature, in contact with said grounded member andhaving a groove in the face thereof adjacent said grounded member and aconducting discharge member mounted in said body portion having aportion thereof extending into said groove but normally spaced from saidgrounded member and means mounted on said support for pressing saiddischarge block against said grounded member, the groove in said bodyportion being open to atmosphere to allow escape of the gas therein Whenit is expanded by the rise in temperature and the electric discharge.

5. In a device of the character described a grounded member, a dischargemember cooperating therewith comprising a body portion of insulatingmaterial which becomes plastic when heated above a pre-determinedtemperature and a conducting member moulded in said body portion androtected thereby, means contacting with sai body portion and conductingmember for pressing the body portion against said grounded member, saidbody portion normally holding said conducting member in spaced relationto said grounded member and distorting out of its normal shape whenheated above a predetermined temperature under the pressure of saidcontacting means to bring said conducting member into engagement withsaid grounded member.

In witness whereof, I hereunto subscribe my name this 17th day of March,A. D. 1923.

WALLACE L. COOK.

